Introduction: Structural realism was born in the attempt to reach a compromise between a realist argument and an antirealist one, namely the ‘no miracle’ argument and the ‘pessimistic meta-induction’, respectively. In recent years, John Worrall has drawn attention to an epistemological version of structural realism, which he traces back to Henri Poincaré. French and Ladyman, on the other hand, have urged a metaphysical or ontic structural realism, which offers a ‘reconceptualisation of ontology, at the most basic metaphysical level, which effects a shift from objects to structures.’ French and Ladyman want to maintain the distance from neo-Kantianism and detach metaphysical structural realism from neo-Kantian epistemology so as to do justice to the realist’s demand for mind-independence. This manoeuvre raises, however, some difficulties that have been at the centre of a recent ongoing debate: can we really ‘dissolve’ entities into mathematical structures? How can we even conceive of structural relations without relata? In this paper the author offers a diagnosis of the current standoff within structural realism between the epistemological and the metaphysical variant, by drawing attention to some important assumptions underlying the structural realist programme, and to their philosophical sources. It is the heterogeneity of these sources – she suggests – that is mainly responsible for the current stand-off within structural realism.

Comment: In this paper the author gives an excellent overview of the philosophical sources of structural realism: Poincaré, Cassier and Russell. The paper also explains with clarity the Newman problem and reviews the Fresnel-Maxwell case. The chapter serves as a good introduction to the topic of Structural Realism. It serves as well as a good introduction to the rest of the chapters present in the same book. This reading is best suited for courses in philosophy of science.

Abstract: Ontic structural realism is at its core the view that ‘structure is ontologically fundamental.’ Informed from its inception by the scientific revolutions that punctuated the 20th century, its advocates often present the position as the perspective on ontology best befitting of modern physics. But the idea that structure is fundamental has proved difficult to articulate adequately, and what OSR’s claimed naturalistic credentials consist in is hard to precisify as well. Nor is it clear that the position is actually supported by our most fundamental physical theories. What is clear, however, is that structuralists have revealed a seam of material at the core of modern physics that is replete with implications for metaphysics. This article surveys some positions subsumed under the rubric of OSR, considering both their warrant and the interconnections that exist between them. The author argues that the fundamental kind properties pose a challenge to ontic structuralism, because it seems that these properties do not supervene upon the relevant structures. The development of structuralist metaphysics will require both an engagement with the details of modern physical theories and the deployment of tools more typically developed in a priori metaphysics. As such, it seems armchair metaphysicians have not just a stake in whether OSR’s claims may ultimately be shown to stand up, but a crucial role to play in getting them to the point where they can be subjected to scrutiny in the first place.

Comment: This paper offers a good overview of Ontic Structural Realism and its two distinct doctrines: eliminative structuralism and priority-based structuralism. It could serve as a specialized reading for postgraduate courses in philosophy of science. Before reading this paper, students should first acquire some knowledge on the basic features of structural realism.